Schools that don’t have designated canteen for the lunch break, like my younger kid’s ESF school, cannot do full time. I think this applies to both local and international schools. The difference, maybe, is that International schools have more autonomy in adjusting the hours in a way to minimize the problem (reducing break times, “stealing “ 5 minutes from every class to make time for every subject...).
My son has been doing reduced school time for quite a while, since August if I remember correctly (only until 2pm with two short snack breaks, the second one being unofficially lunch)
Some private or semi private local schools have a decent amount of space and proper canteens. They never resumed full day class... Something doesn't add up here. Or they don't want to push with EDB for full day teaching or international schools receive special treatment...